The present invention generally relates to a disc apparatus for reading out information from a disc recording medium as a flexible disc (FD) or the like. The present invention is more particularly concerned with the disc apparatus, including a driving mechanism rotatively driving the disc recording medium and a head reading out information from the disc recording medium, improved in the reading out information just after the disc recording medium has been loaded into the disc apparatus.
The disc recording media such as flexible disk (FD) are used as auxiliary storage media in many types of information processing equipment (such as office computers, word processors and the like). The fundamental configuration of the entirety of such an information processing apparatus is as indicated in FIG. 9.
The information processing apparatus 20 includes a central processing unit (hereinafter termed a CPU) 21 that performs control of the entirety, a memory 22 that performs write and read of information by the CPU 21, and I/O units 23 such as displays and the like, a flexible disc drive control circuit (hereinafter termed a FDD control circuit) 24. The CPU 21, the memory 22, I/O units 23 and the FDD control circuit 24 are connected by a bus 25. Multiple flexible disc drive apparatus (hereinafter termed FDD) 30(1) through 30(n) are provided to the information processing apparatus 20. That is, each of the FFD 30(1) through FDD 30(n) are connected to the FDD control circuit 24 by a FDD bus 26.
The FDD 30(1) through 30(n) drive 3.5 inch flexible discs for example, and have a configuration as disclosed in "UPDATE FLOPPY DISC APPARATUS AND APPLICATION KNOW-HOW THEREOF" (S. TAKAHASHI CQ Publication Inc. 1984).
Each of the FDD 30(l) through 30(n) are provided with a drive mechanism that rotates the flexible disc and a head that reads out and writes information from and to the flexible disc. The drive mechanism includes a motor rotating the flexible disc and a chucking mechanism provided on a shaft of the motor. When the flexible disc has been loaded into the FDD, the motor rotates and the center of the flexible disc is positioned to the rotative shaft of the motor and then the flexible disc is supported and fixed by the chucking mechanism (chucking operation).
The FDD control circuit 24 performs drive control of each of the FDD 30(1) through 30(n) on the basis of instructions from the CPU 21. Index pulses in synchronization with the rotational cycle of the flexible disc and the read data are output from the FDD. The control relating to data read from the FDD is as described in the following.
The FDD control circuit 24 outputs two types of signals for data output requests from CPU 21. These two types a the MOTOR ON signal and a DRIVE SELECT signal. The MOTOR ON signal is a signal that performs the motor drive instruction. The DRIVE SELECT signal is a signal that indicates which of a plural number of FDD 30(1) through 30(n) has been selected. This DRIVE SELECT signal is output from the FDD control circuit 24 even if there is only one FDD connected. The motor of the specified FDD by the DRIVE SELECT signal from the FDD control circuit 24 is driven according to the MOTOR ON signal. When the motor has been driven and the flexible disc has rotated, the read data and the index pulses are output from the FDD. The FDD control circuit 24 inputs the read data and the index pulses output from the FDD via FDD bus 26. Then the FDD control circuit 24 supplies the read data and the index pulses to the CPU 21 via the bus 25.
As aforementioned, when the FDD is supplied the MOTOR ON signal from the information processing apparatus 20, immediately the motor of the FDD is rotated and then the read data and the index pulses are output from the FDD.
The conventional disc apparatus such as the FDD above described does not perform the right data reading, if the motor rotation control signal (such as the MOTOR 0N signal) is supplied from the information processing apparatus (accessed from the information processing apparatus) during the chucking operation just after the flexible disc is loaded into the disc apparatus. Because the rotation of the disc is especially unstable during the chucking operation. The data read out during the chucking operation causes errors in the information processing apparatus supplied with the data.